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CVE-2026-23308 Linux CVE debrief

A logic error in the Linux kernel's pinctrl equilibrium driver causes spurious warning traces during GPIO initialization. The `eqbr_irq_mask_ack()` callback incorrectly invokes `eqbr_irq_mask()`, which internally calls `gpiochip_disable_irq()`. This triggers a WARN_ON trace for every GPIO at load time because the interrupt is being disabled in a context where it should not be. The issue affects Linux kernel versions 6.4 through 6.6.129, 6.7 through 6.12.76, 6.13 through 6.18.16, 6.19 through 6.19.6, and 7.0-rc1/rc2. The fix implements the mask-ack logic directly without calling the separate mask function, avoiding the improper interrupt disable. This is a local denial-of-service condition that generates log noise and potential boot delays, but does not enable privilege escalation or information disclosure.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-03-25
Original CVE updated
2026-05-28
Advisory published
2026-03-25
Advisory updated
2026-05-28

Who should care

Linux system administrators running kernels with the equilibrium pinctrl driver enabled; embedded device manufacturers using affected kernel branches; security teams monitoring for kernel warning anomalies that may mask more serious issues

Technical summary

The equilibrium pinctrl driver for the Linux kernel contains a logic flaw where `eqbr_irq_mask_ack()` calls `eqbr_irq_mask()`, which in turn calls `gpiochip_disable_irq()`. This generates a warning trace at boot for every GPIO because the disable operation is inappropriate in the mask-ack context. The vulnerability is local-only with no security boundary crossing, but creates denial-of-service conditions through log flooding and potential boot delays. The fix refactors `eqbr_irq_mask_ack()` to implement the mask and ack operations directly without invoking the helper functions, matching the pattern used in the similar starfive-jh7100 pinctrl driver.

Defensive priority

medium

Recommended defensive actions

  • Apply the appropriate stable kernel patch for your version branch: 6.6.130+, 6.12.77+, 6.18.17+, 6.19.7+, or 7.0-rc3+
  • Monitor kernel logs for 'gpiochip_disable_irq' warnings on affected systems as an indicator of unpatched status
  • If running custom kernels with the equilibrium pinctrl driver, cherry-pick the fix from the stable kernel git repository
  • Consider backporting the patch to long-term support kernels if vendor patches are not yet available
  • No runtime workaround exists; patching is required to eliminate the warning traces

Evidence notes

The vulnerability description and patch references confirm the issue is a warning trace generated by improper `gpiochip_disable_irq()` calls in `eqbr_irq_mask()` when invoked from `eqbr_irq_mask_ack()`. The fix removes the helper function calls and implements the logic directly. CVSS 5.5 (MEDIUM) reflects local attack vector with availability impact.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-23308 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-23308

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-23308 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-23308

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/3e00b1b332e54ba50cca6691f628b9c06574024f

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/53eba152810ef0fff8567b13ea0f62d48e62df6b

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/896449ad9053a42c6c710aeae6175170176cabd0

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/af3b0ec98dc1133521b612f8009fdd36b612aabe

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

  • Mitigation or vendor reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/ec54546e8d8a50a9824c139a127a8459d1b0b1bb

    416baaa9-dc9f-4396-8d5f-8c081fb06d67 - Patch

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.